Metal complexes of sulphur ligands. Part IX. Synthesis of dimethylphosphinodithioato-complexes of ruthenium(II) containing bidentate donor ligands

Abstract

The tris(chelate) complexes [Ru(S₂Pme₂)₂(diene)]{diene = bicyclo[2.2.1]hepta-2,5-diene (nbd) or cyclo-octa-1,5-diene (cot)} have been synthesised by the reaction of [{RuCl₂(diene)}_n] with Na[S₂Pme₂]·2H₂O in either ethanol or NN-dimethylformamide. The labile diene moiety is readily replaced by various chelating ligands to give [Ru(S₂Pme₂)₂(L–L)]{L–L = Ph₂P[CH₂]₂PPh₂(dppe), Ph₂PCH₂PPh₂(dppm), C₆H₄(AsMe₂)₂(pdma)}. For L–L = pdma, trans-[Ru(S₂Pme₂)₂(pdma)₂] is also formed. Unlike the corresponding cis-[Ru(S₂Pme₂)₂L₂][L = PR₃ or P(OR)₃], all the tris(chelate) complexes exhibit very slow rates of optical inversion and this evidence is used to tentatively propose a modified inversion mechanism of that postulated earlier.